This invention relates to electric lamp socket switches of the rotary type, and more particularly to an external attachment by which electric lamp socket switches of the rotary thumb wheel type are rendered operable by a pull chain.
There are a variety of commercially available electric lamp socket switches which are constructed internally for operation by a pull chain. They are convenient for use in table and floor lamps since the pull chain is disposed for ready access. However, they involve the assembly of a considerable number of parts and therefore are expensive to manufacture and are susceptible of malfunction after limited use.
There also are a variety of commercially available electric lamp socket switches which are constructed internally for operation by a horizontal rotary shaft extending laterally from the socket housing and fitted at its exposed end with a thumb wheel for manual operation. They involve significantly fewer parts than the pull chain type and therefore are less expensive and have considerably longer service life. However, the thumb wheel generally is located in a position, such as under a lamp shade, of difficult or inconvenient accessibility.
U.S. Pat. No. 3,643,052 discloses an operator capable of attachment to the horizontal rotary shaft of an electric lamp socket switch, in place of the thumb wheel, for operating the shaft by a pull chain.